Propeller for ships.



G. GARDOSA.

PROPELLER FOR SHIPS.

APPLICATION FILED JAN. 21, 1911.

1,086,274,- Patented Feb. 3, 1914.

' jmrah G. Caz-(dam UNITED STATES PATENT oFnIoE.

GIOVANNI CARDOSA, OF VENICE, ITALY, ASSIGNOR OF ONE-HALF TO NICOLO SPADAOF VENICE, ITALY;

raorannnn 'ron snr'rs,

Specification of Letters ratent.

Patented Feb. 3, 1914,

To all whom it may concern:

Be it known that I, GIOVANNI CAnnosA, a subject of the King of Italy,and residing at S. Maria del Giglio, Venice, Italy, have inventedcertain new and useful Improvements in Propellers for Ships, of whichthe following is a specification, reference being had therein to theaccompanying drawing.

The present invention relates to improvements in propellers for shipswith flat blades which form with the axis of the propeller an angle ofabout 45 and whose parallel entrant and exit edges form an angle of 45or closeto 45 with the perpendicular line to the axis which passesthrough the plane of the blade.

The improvement whichIhave introduced in these propellers has for itsobject to construct an eflicient propeller with the angle between theblades and the axis of-the propeller other than 45. According to thisinvent-ion, this'angle may be varied and may even exceed 80, and itsvalue is given geometrically by the angle which will be formed in theright angle triangle by the hypotenuse and a cathetus which is equal tothe theoretical advance of the propeller, the other cathetus of thistriangle being equal to twice the diameter of the said propeller. r,

A propeller constructed according to the present invention may be usedalso with mo tors of great power and with a relatively large number ofrevolutions. It is well known that when the number of revolutions 'of amotor with a given power is increased,

axis of the propeller is 45, it would be an ang necessary, in order toobtain the required small theoretical advance, to vary the diameter ofthe propeller and therefore, to diminish the power employed, as theangle between the blades and the axis of the propeller may not bealtered.

The improved propeller is shown in the accompanying drawings in which:

Figure 1 represents a blade whose plane is parallel to the plane of theaper, Fig. 2 is a projection of the blade an Fig. 3 showsdiagrammatically the geometrical construction of the angle between theblade and the axis of the propeller.

. 0 and dare-two blades which have two sides m and n parallel to eachother and an' extremity p, preferably curved.

B is the angle between the blades and the axis of the propeller and mayhave any value up to and even exceeding 80. It is formed by thehypotenuse O B and the cathetus C A of a right angle triangle, saidcathetus being equal to the theoretical advance of the propeller, whilethe other cathetus is equal to twice the diameter of the propeller.

What I claim is:

A propeller for ships with flat blade whose parallel entrant and exitedges form pendicular line to the axis which passes through the plane ofthe blade, and in which the blades form with the axis of the propelleran angle of up to or exceeding 80,

this angle being given geometrically by the angle formed in a' rightangle triangle-by the hypotenuse and a cathetus equal to the theoreticaladvance of the ropeller, the second cathctus of this t-riang e beingequal to twice the diameter of the said propeller.

In witness whereof I, said GIOVANNI CAR- DOSA, have signed thisspecification at Rome in the Kingdom of Italy this 7th day of January,1911.

GIOVANNI CARDOSA. In the presence of two witnesses:

LOBBORUTI FuANoEsIo, VALENTI ARMANOLO.

e of 45 or close to 45 with the per-

